The present invention relates generally to abrasive devices. Stated more particularly, the present patent discloses and protects a removably attachable abrasive disk, which may be used in combination with a particularly designed sanding pad, that is particularly designed for use relative to motorized rotary drywall sanding tools.
One knowledgeable in the art of drywall installation will be well aware that, after the joints between adjacent panels have been filled and taped, the proper installation of drywall requires that the installer sand each joint to reduce it to the level of each adjacent drywall panel thereby smoothing it over such that all evidence of the joint is eliminated after painting.
In the past, and still to a lesser extent today, this necessary sanding has been performed manually, typically with a sheet of sandpaper wrapped around a sanding block. To improve reach, sanding blocks have been hingedly coupled to an end of an elongate pole. As any person who has engaged in either method of sanding will attest, manual sanding by either method quickly proves to be laborious and tiresome.
Advantageously, a number of prior art inventors have developed motorized sanders that retain a typically round or rectangular article of abrasive material, such as sandpaper, and rotate or reciprocate the abrasive sanding article rapidly. With this, the abrasive sanding article can be applied to a drywall panel to be sanded thereby improving a worker""s speed and efficiency. Indeed, a number of motorized sanders have been disclosed that are directed particularly to the art of drywall sanding. By way of example, a motorized drywall sander and improvements thereto are described in U.S. Pat. Nos. 4,782,632 and 5,239,783, both to Matechuk and both entitled xe2x80x9cDrywall Sander.xe2x80x9d
Typically, the abrasive sanding article employed relative to motorized drywall sanders comprises an annular abrasive sanding disk with a concentric annular cutout in the center thereof. When the abrasive sanding article comprises a disk, a back-up pad is normally used to mount or attach the abrasive sanding disk to the drywall sander. Certain prior art back-up pads have a first side to which the abrasive sanding disc is attached and a second side from which a bolt or screw extends to couple to the sanding head of the drywall sander. In other cases, the sanding head has an abrasive sanding disc adhered to a sanding pad, and the two are mounted concentrically on a sanding drive plate such that the abrasive sanding disk can be driven rotatably by a flexible drive shaft. The sanding pad and abrasive sanding disk can be mounted in contact with a sanding drive plate in a shroud by a washer and nut that threadedly engage a retaining spindle that extends from the sanding head. Alternatively, the sanding pad and abrasive sanding disk can be fixed in place by a retaining bolt and washer that pass through the central aperture in the pad and disk and into engagement with the sanding drive plate.
Unfortunately, a number of problems derive from these prior art constructions. Indeed, since the initial introduction of motorized drywall sanders, practitioners in the art have been confronted with issues relating to the attachment, wear, and removal and replacement of the abrasive sanding panels that are coupled to the sanding head of motorized drywall sanders. For example, removing and replacing the sanding pad and abrasive sanding disk on prior art drywall sanders typically requires a user to employ a tool, such as a screwdriver or wrench. This inevitably results in inconvenience and work stoppage for the user.
Furthermore, the central apertures in the sanding pad and the abrasive sanding disk commonly increase the vulnerability of the abrasive sanding disk, and possibly the sanding pad, to tearing when the drywall sander encounters a significant irregularity, such as an electrical outlet or the like, in the surface to be sanded. Not only is a tear in the abrasive sanding disk detrimental because it compels early replacement of the disk, but it is also problematic because the material used to cover drywall tape and to fill the joints between adjacent panels and in screw indentations is easily abraded. Also, the paper surface of the drywall panels can be damaged easily when sanding. A torn or otherwise damaged abrasive sanding disk can quickly result in scoring or other damage to the surface. Absent time consuming repair, such damage mars the appearance of the finished work.
A number of solutions to the problem of providing a readily removable and replaceable abrasive sanding disk have been attempted. For example, U.S. Pat. No. 5,239,783 discloses attaching the abrasive sanding disk to a drive plate by a twist-lock, bayonet-type fastener that takes the place of the retaining bolt of earlier devices. However useful, such a fastener nonetheless leaves uncured the problems that derive from having a central aperture in the abrasive sanding disk and the expense resulting from having to replace the abrasive sanding disk and sanding pad unitarily.
Other prior art inventors have developed systems for removably coupling the abrasive sanding disk to the sanding pad by means of hook and loop fasteners. Under these systems, hook fasteners are disposed on a facing surface of either the abrasive sanding disk or the sanding pad while loop fasteners are disposed on a facing surface of the other of the abrasive sanding disk and sanding pad. With this, the abrasive sanding disk can be removed and replaced relative to the sanding pad by pulling the hook fasteners out of engagement with the loop fasteners. Unfortunately, such devices exhibit a number of problems. For example, the hooks and loops in such devices commonly become clogged with sanding debris and the like.
Yet another flawed practice that has been used in the past is to bond the sanding disk to the sanding pad by use of what is termed a feathering adhesive. Such a practice is described particularly in U.S. Pat. No. 4,558,542 to Marton for a xe2x80x9cStick-On Abrasive Disc.xe2x80x9d Unfortunately, this practice is disadvantageous for a number of reasons. For example, a user must apply the adhesive or glue both to the disk and to the backup pad by applying it to each individually or by applying the glue to the abrasive sanding disk and then rubbing the disk against the sanding pad to spread the adhesive evenly.
By doing so, adhesive can get onto the abrasive side of the disk whereupon it can get onto and mar or damage the surface to be sanded. The adhesive also can plug up the sanding disk. Still further, the sandpaper in many cases tears up in use and also when the operator tries to remove it from the backup pad thereby leaving small pieces or chunks of the abrasive sanding disk. Consequently, completely removing the sanding disk from the sanding pad is nearly impossible whereby a user must glue a new disk over the remaining portions of previous disks. With this, the new disk does not lie flatly and presents an uneven and unbalanced operative surface that can lead to a marking of the surface to be sanded, uneven wear on the abrasive sanding disk, and a tearing of the disk during use.
A still further deficiency exhibited by prior art abrasive sanding disks for drywall derives from their overall configuration. As was noted above, drywall abrasive sanding disks are manufactured as round disks with a concentric, round aperture formed therein. That round aperture is necessary to allow access to the fastener arrangement that fixes the sanding pad in place. Disadvantageously, the central aperture presents an additional edge on the abrasive sanding disk that can, and often does, catch on anomalies, such as an open utility box in a sheet of drywall, in a surface to be sanded. With this, the disks often tear apart thereby leading to added expense and loss of active work time.
In light of the foregoing, one will appreciate that, notwithstanding the plurality of abrasive structures that have been disclosed by the prior art, there remains a need for an abrasive sanding disk and sanding pad particularly designed for drywall sanding that are durable, effective, and easily removable and replaceable.
Advantageously, the present invention is founded on the basic object of providing an abrasive sanding disk and sanding pad that are particularly crafted for sanding drywall and that meet the needs as of yet left unmet by the prior art.
A more particular object of the invention is to provide an abrasive sanding disk for drywall sanding that can be removed and replaced quickly and easily relative to a sanding head of a drywall sander.
A further object of the invention is to provide an abrasive sanding disk particularly designed for drywall sanding that demonstrates added durability over prior art abrasive sanding disks.
Still another object of the invention is to provide an abrasive sanding disk that demonstrates improved drywall sanding results as compared to prior art abrasive sanding disks.
Yet another object of the invention is to provide an abrasive sanding disk that resists causing damage to a drywall surface to be sanded.
An even further object of the invention is to provide an abrasive sanding disk and sanding pad combination that allows a plurality of abrasive sanding disks to be used relative to a particularly crafted sanding pad without requiring replacement of the sanding pad.
Of course, these and further objects and advantages of the invention would be readily obvious not only to one skilled in the art who reviews the present disclosure and the accompanying drawing figures but also to one who has an opportunity to take advantage of an embodiment of the present invention.
In accomplishing the aforementioned objects, a most basic embodiment of the invention comprises an abrasive sanding disk and sanding pad combination for use in sanding drywall surfaces by use of a motorized drywall sander with a sanding head. The abrasive sanding disk is founded on a flat, circular substrate panel that, in a marked deviation from prior art abrasive sanding disks for drywall sanders, is devoid of a central aperture. The substrate panel has a first face comprising a sanding head facing face for facing a sanding head of a drywall sander and a second face comprising an abrasive face for abrading a given surface. The sanding pad, which is designed to be interposed between the abrasive sanding disk and a sanding head of a drywall sander, comprises a round disk of resiliently compressible material with a concentric central aperture. The sanding pad has an abrasive disk engaging face for engaging the abrasive sanding disk and a sanding head engaging face for engaging the sanding head of the drywall sander.
A layer of adhesive, ideally pressure sensitive adhesive, is preferably disposed over substantially the entire sanding head engaging face of the substrate panel. With this, the abrasive sanding disk can be affixed to a sanding head of a drywall sander by applying the sanding head engaging face of the substrate panel to the sanding head. Even more preferably, a flexible protective film can overly the layer of pressure sensitive adhesive on the sanding head engaging face to cover and protect the layer of pressure sensitive adhesive. Advantageously, the layer of pressure sensitive adhesive can be exposed by a peeling of the protective film away from the layer of pressure sensitive adhesive. Most preferably, the abrasive sanding disk will have a diameter of about nine inches, which will ensure its proper coupling to a standard drywall sander.
In certain preferred embodiments, the abrasive disk engaging face of the sanding pad will comprise a smooth surface. With this, the layer of pressure sensitive adhesive of the sanding head facing face of the abrasive sanding disk can be applied to the abrasive disk engaging face of the sanding pad and peeled therefrom without damage to the abrasive sanding disk or the sanding pad. Ideally, the sanding head engaging face of the sanding pad will be textured to improve frictional contact between the sanding head engaging face of the sanding pad and the sanding head.
With certain embodiments of the present invention for an abrasive sanding disk and sanding pad combination generally described, one will appreciate that the foregoing discussion broadly outlines the more important features of the invention merely to enable a better understanding of the detailed description that follows and to instill a better appreciation of the inventor""s contribution to the art. Before any particular embodiment of the invention is explained in detail, it must be made clear that the following details of construction, descriptions of geometry, and illustrations of inventive concepts are mere examples of the many possible manifestations of the invention.